Conventionally, there have been available light source devices in which a discharge lamp, a laser oscillator, or the like have been used as a light source. In recent years, a variety of light source devices employing an LED (Light Emitting Diode) module as a light source has been proposed in an effort to seek reduced power consumption and prolonged lifespan. For example, an LED module whose emission wavelength is set to fall within an ultraviolet region is used as an ultraviolet irradiation source in an ultraviolet irradiation device for irradiating ultraviolet rays on an ultraviolet curable resin such as paint, an adhesive agent, a pigment, or the like to thereby cure and dry the ultraviolet curable resin.
In the LED module for use in this kind of light source device, an LED chip is mounted within a package. The LED module is manufactured by arranging a plurality of packages side by side so as to obtain a desired light quantity. An LED chip with high output power is used as the LED chip. The LED chip is set so as to obtain a desired light quantity.
If the LED chip emits a light by supplying an electric current to the LED module, the LED chip generates heat. As stated above, the LED module of this kind makes use of a plurality of LED chips. Therefore, the LED module generates an increased amount of heat. The emission efficiency of the LED chip has a negative temperature coefficient. This poses a problem in that, if the amount of heat generated by the LED chip becomes larger, the emission efficiency of the LED module gets lower.
Just like an LED mounting structure as disclosed in, e.g., JP2006-100687A, there are proposed an LED module with an enhanced heat dissipation effect and a mounting structure thereof. In the LED mounting structure disclosed in JP2006-100687A, a substrate is formed by stacking an insulating layer, wiring patterns, and a resist on the upper surface of a base member made of metal having high heat conductivity. A package equipped with an LED chip is mounted on the surface of the substrate. At this time, the insulating layer or the resist of the substrate positioned at the bottom surface side of the package is removed. A heat transfer member such as silicon rubber or the like is arranged between the package and the base member. As a result, the heat generated from the LED chip is dissipated via the heat transfer member and the base member, thereby enhancing the heat dissipation effect.
In order to manufacture the LED module disclosed in JP2006-100687A, however, there is a need to first stack the insulating layer, the wiring patterns, and the resist on the base member and then secondly, to remove the insulating layer, the wiring patterns, and the resist from the region over which the package is to be mounted. The heat transfer member is arranged in the region from which the insulating layer, the wiring patterns, and the resist are removed. The package equipped with the LED chip is arranged on the heat transfer member. Electrodes arranged in the package are soldered to the wiring patterns. The manufacturing process of the LED module disclosed in JP2006-100687A is too complex.